Schedule Sep 10, 2001
A Dissipative Approach to the Figure/Ground Problem
Dr. Mary Pugh, University of Toronto
In this talk I will present some work in progress in vision research. We consider the problem of recognizing what parts of an image are perceived as being in the foreground. We use a variant of the Pao-Geiger-Rubin model, which uses an energy dissipation approach to this problem. The model is surface-based, rather than contour-based. Specifically, the edges in the image are not viewed as isolated contours, but are viewed as bounding a surface. Each local edge has a local hypothesis; for example, a north-south edge might think "the region immediately to the left of me is part of the figure". The model then uses energy dissipation methods to seek assignments of local hypotheses that are mutually agreeable, yielding a segmentation of the image that might be perceived. We test the model on various images to address questions like: does the model "perceive" smaller objects to be in the foreground (the way we do)? convex objects to be in the foreground (the way we do)? how does it perform on optical illusions that viewers report to have two different segmentations? This is joint work with Nava Rubin of the Center for Neural Science, NYU. I thank Anita Disney (CNS, NYU), Davi Geiger (Courant, NYU), Bob Shapley (CNS, NYU), and Dave McLaughlin (Courant, NYU) for useful discussions.

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